ANT COMMUNITY COMPOSITION AND SEED REMOVAL IN LONGLEAF PINE FORESTS MANAGED WITH FREQUENT FIRE By RACHEL A. ATCHISON A THESIS PRESENTED TO THE GRADUATE SCHOOL OF THE UNIVERSITY OF FLORIDA IN PARTIAL FULFILLMENT OF THE REQUIREMENTS FOR THE DEGREE OF MASTER OF SCIENCE UNIVERSITY OF FLORIDA 2020 © 2020 Rachel A. Atchison To Myra Atchison who gave me her love of reading—a necessary precursor to research. ACKNOWLEDGMENTS Thanks to my advisor Dr. Andrea Lucky for advocating for me to me—reminding me of the breadth of my experiences as a scientist, encouraging application to grants that funded my master’s research, and for her flexibility in allowing me to craft the program that would benefit me the most. Thanks to my mentor and committee member Raelene Crandall for the inspiring talks about experimental design and statistics and her overall enthusiasm for my project. This work was supported financially by the National Science Foundation Graduate Research Fellowship under Grant No. DGE-1315138 and and DGE-1842473, and the UF Ordway Swisher Biological Station Jumpstart Award. I am grateful to everyone in the Lucky lab for all their feedback and putting up with (and sometimes even enjoying) my little singing outbursts. Everyone on my field team: Katie, Sara, James, Lexie, and Cassie—thanks for all the dirty, sweaty days in the field and meaningful conversations and singing on the drives to and from the field. Constance and Emily provided much needed sorting assistance. A special thanks goes to Chiappini’s for providing my field team with refreshments and a connection to the Melrose community to share our research with. I thank all the employees at Ordway- Swisher Biological Station for facilitating my research, especially Andy Rappe who helped in site selection, and Lisa Huey who assisted with plot set-up. The Entomology office staff, Nancy, Beth, Laura, Glinda and Linda helped me navigate departmental resources and a mileu of paperwork. I am tremendously appreciative of my kind friends—of which there are too many to list—you have been a great support, offering comradery and solidarity, and reminding me of my strengths when I felt particularly overwhelmed. Finally, I thank my husband Jon for listening to all my complaints and initiating many high-fives. 4 TABLE OF CONTENTS page ACKNOWLEDGMENTS .................................................................................................. 4 LIST OF TABLES ............................................................................................................ 7 LIST OF FIGURES .......................................................................................................... 8 LIST OF ABBREVIATIONS ............................................................................................. 9 ABSTRACT ................................................................................................................... 10 CHAPTER 1 MANAGED FIRE FREQUENCY SIGNIFICANTLY INFLUENCES THE LITTER ARTHROPOD COMMUNITY IN LONGLEAF PINE FLATWOODS ........................ 12 Introduction ............................................................................................................. 13 Materials and Methods............................................................................................ 18 Sampling Site ................................................................................................... 19 Treatments ....................................................................................................... 19 Sampling Design .............................................................................................. 21 Statistical Analyses .......................................................................................... 22 Results .................................................................................................................... 23 Burn Frequency Effect on Species Richness ................................................... 24 Burn Frequency Effect on Community Composition ......................................... 25 Native and Exotic Species ................................................................................ 27 Discussion .............................................................................................................. 28 Species Richness and Community Composition .............................................. 29 Exotic Species .................................................................................................. 30 Native Species ................................................................................................. 32 Conclusion ........................................................................................................ 33 2 SEED-REMOVING ANT SPECIES IN LONGLEAF SANDHILL ARE RESILIENT TO FREQUENT FIRE………………………………………………………………….. .. 42 Introduction ............................................................................................................. 43 Materials and Methods............................................................................................ 42 Study Site ......................................................................................................... 46 Experimental Design ........................................................................................ 47 Statistical Analyses .......................................................................................... 51 Results .................................................................................................................... 54 Seed-Removing Species .................................................................................. 54 Community Response to Fire ........................................................................... 56 Seed-Removal Activity ..................................................................................... 57 Discussion .............................................................................................................. 58 5 Seed-Removing Species .................................................................................. 59 Community Response to Fire ........................................................................... 64 Seed-Removal Activity ..................................................................................... 66 Conclusions ...................................................................................................... 67 3 SYNTHESIS ........................................................................................................... 82 APPENDIX A SUPPLEMENTAL TABLES .................................................................................... 83 B SUPPLEMENTAL FIGURES .................................................................................. 84 LIST OF REFERENCES ............................................................................................... 88 BIOGRAPHICAL SKETCH .......................................................................................... 100 6 LIST OF TABLES Table page 1-1 Ant and termite species occurrence in forest plots managed with different burn regimes, out of 30 collections per treatment. .............................................. 36 1-2 Pairwise comparisons of ant species density across fire frequency treatments . 40 2-1 Sampling dates by sampling method .................................................................. 69 2-2 Seed-removers identified in our and other studies ............................................. 70 2-3 Species detection (percent found in out of total sample units) by sampling method ............................................................................................................... 73 2-4 Non-parametric multivariate analysis of variance leaf litter community composition analyses ......................................................................................... 78 2-5 GLM Model Analysis of Deviance: proportion of seed removed ......................... 80 2-6 Non-parametric multivariate analysis of variance analyses of seed-removal trial composition .................................................................................................. 80 A-1 Coarse downed wood (CDW) volume measurements (OSBS study) ................. 83 7 LIST OF FIGURES Figure page 1-1 Sampling site with transect locations. ................................................................. 35 1-2 Sample-based rarefaction across all treatments................................................. 37 1-3 Species rarefaction, richness, and richness estimates by treatment .................. 38 1-4 Fire frequency effect on species density ............................................................ 39 1-5 NMDS of ant community composition ................................................................. 40 1-6 Ten most abundant ant species per treatment ................................................... 41 2-1 Diagram of burn treatment plots at OSBS. ......................................................... 69 2-2 Species accumulation curves by sampling type. ................................................ 72 2-3 Seed-removing ant species: percent seed removed. .......................................... 76 2-4 Species’ contribution to beta diversity ................................................................ 76 2-5 NMDS for litter ant community composition: overall versus seed-removers. ...... 77 2-6 Sampling period effects on species richness and amount of seeds removed .... 79 2-7